The boost sleeve increases line pressure for shift quality, engagement and proper TCC apply. As the sleeve wears, torque signal oil will leak to exhaustand line pressure will not increase as commanded.
These Sonnax kits restore proper clearance with upgrade design and material to prevent EPC and reverse boost loss. Increased performance and OEM ratio kits are available.
Vehicles with a 5L40-E transmission are prone to poor line rise or high reverse pressure problems causing poor shift quality and clutch failure due to leakage at the boost valve assembly. Sonnax offers two replacement boost assemblies: the 55209-01K with large ratio (higher line rise and firmer shifts) and the OE ratio 55209-04K for factory performance.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
November 24, 2015
Topics: Vacuum Test Guides Vacuum Testing Transmission GM 5L50-E Transmission 5L40-E TransmissionRead Now
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A Wet Air Test shows leakage between the EPC and Reverse ports or a Vacuum test is less than 18".